What are the Lines that run up and down and from side to side on a map?

The lines that run up and down on a map are called longitude lines, while the lines that run from side to side are called latitude lines. Longitude lines measure the distance east or west of the Prime Meridian, while latitude lines measure the distance north or south of the Equator. Together, these lines form a grid system that helps in identifying specific locations on the Earth's surface.